The present invention relates to implantable, expandable, multicontact electrodes. In a preferred embodiment, such electrodes comprise deployable, paddle-type, multicontact electrodes useful for spinal stimulation.
There are two major types of electrodes used for spinal stimulation: (1) percutaneously implanted in-line electrodes/leads requiring local anesthesia for implant, and (2) paddle-shaped electrodes requiring major surgery for implantation.
The first type of electrodes, i.e., the in-line electrodes, comprise thin, rod-type electrodes. Such in-line or rod-type electrodes are easy and less invasive to implant, typically requiring only local anesthesia and the use of a large gauge needle. Disadvantageously, such in-line electrodes are not as stable as paddle leads, and are prone to migration.
The second type of electrodes, i.e., the paddle-shaped electrodes, provide a large-area electrode surface to contact the body tissue, much like a miniature ping-pong paddle. Advantageously, such paddle-type electrodes are more effective and stable than in-line electrodes. Moreover, such paddle-type electrodes provide a platform for multiple electrodes in many possible configurations to thereby optimize electrode programming and clinical results. In contrast, the percutaneous in-line electrodes can only combine electrodes in a vertical row. Disadvantageously, however, the paddle-type electrodes require complex major surgery for implantation, along with all the attendant risks associated with major complex surgery.
It is thus evident, that there is a need in the art for an electrode which can deliver the maximum advantages of the paddle-type electrodes, but without requiring extensive surgery for implantation.